The manufacture of golf balls involves a series of sequential processes performed at different stations. After one production process, it is sometimes necessary to change the orientation of the ball to optimize the performance of a subsequent process. For example, automated imaging inspection of golf ball indicia calls for an optimal golf ball positioning with respect to the camera that inspects the indicia.
Achieving a particular orientation is typically a two-step process. First, a golf ball's initial orientation must be ascertained. Second, the ball must be re-oriented.
Regarding the second orienting step, at least two distinct rotational movements can be used to accomplish orientation of a randomly positioned golf ball or other spherical object. With reference to the globe, the first move brings the poles to the vertical orientation. The second move rotates the ball about the polar axis to bring a longitudinal line to the front. Three rotational movements can also be used. The first movement is about a first axis. The second movement is about any second axis, which does not need to be perpendicular to the first axis. The third movement is about any third axis that is perpendicular to the second axis.
Several conventional detection and analysis systems produce images of golf balls to determine a required degree of repositioning for further processing, but they do not accurately orient golf balls. For instance, U.S. Pat. No. 5,611,723 discloses a detection, analysis, and modification system implemented to adjust the attitude of golf balls by rotating them about several axes before they undergo a subsequent de-burring process. This system detects and images golf balls to determine their relative positioning with respect to a predetermined golf ball attitude. The system then calculates the degree of modification required to achieve the predetermined attitude. In two motions, it rotates the golf balls to approximate the attitude, further images the balls, and finely tunes them to the desired attitude. This system, however, does not orient the ball. Plus, as the golf balls are picked up and put down during their transfer from one station to another, this system can tend to shift the balls, which introduces error into the positioning process.
Such shift or slip often occurs as a ball is picked up from one processing station and placed in another. As a golf ball is moved from one station to another, misalignment between a transfer mechanism element and a processing station can cause the ball to rotate, which accidentally changes its orientation so as to nullify the original image data that dictates the current automatic orientation. This rotational shift ultimately leads to an inaccurate orientation of the ball.
Other systems, while reducing such shift allows only one axis of rotation as the balls are moved out of a printing station. One such system is disclosed in commonly owned U.S. Pat. No. 6,630,998 B1, issued on Oct. 7, 2003, which is incorporated herein by reference in its entirety. This system teaches, among other things, an active golf ball indexer that uses a plate clamped into place to allow only one axis of movement while the balls are moved out of the printing operation. A metal arm with a suspended dog actuated by an air cylinder rotates the balls to view and analyze all indicia.
Other systems attempt to avoid rotational transfer shift by orienting golf balls in a single station. Before a golf ball is moved from the orienting station, these systems sequentially rotate the golf ball three separate times to achieve a desired orientation. As a result, excess time is spent orienting golf balls, which likewise can slow production.
The prior art, does not quickly orient golf balls while minimizing inaccuracy due to rotational shift or slip that occurs during golf ball transfer from one processing station to another.